Masking system using masking piece

ABSTRACT

In a masking system a robot performs first conveyance work of making an object gripping unit grip an object and set the object at a predetermined position based on positional information of the object which was detected by a first detection unit, coating work of making a coating unit coat an adhesive on a masking location of the object which is set at the predetermined position, and second conveyance work of making a masking piece gripping unit adhere a masking piece to the masking location of the object based on positional information of the masking piece which was detected by a second detection unit.

RELATED APPLICATIONS

The present application is based on, and claims priority from, JapaneseApplication Number 2011-026006, filed Feb. 9, 2011, the disclosure ofwhich is hereby incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present invention relates to a masking system which performs maskingwork in advance for obtaining a nonpainted location at the time ofpainting.

BACKGROUND ART

If there is a place where paint is not desired in painting work, thatplace is covered with masking tape. Alternatively, that place is coveredby a masking sheet and the ends of the masking sheet are attached bymasking tape.

Further, in Japanese Patent Publication (A) No. 6-99118, a maskingmember is placed on one surface of the object to be painted and magnetsare placed at the other surface so as to fasten the masking member inplace. With this technique, the masking member will not shift at thetime of painting. Further, the masking member can be easily attached anddetached.

However, when using only masking tape and when attaching a masking sheetby masking tape, masking a desired shape is troublesome. Skill on thepart of the worker becomes necessary. The same is true even if using amasking material comprised of a polyethylene or polyurethane resin etc.

Further, when coating a masking member together with the workpiece, itis difficult to accurately trace the shape of the workpiece. This canbecome a cause of a drop in painting quality. Further, the technique ofusing magnets to fasten a masking member such as in Japanese PatentPublication (A) No. 6-99118 sometimes cannot be applied depending on thematerial or shape of the workpiece, so lacks general applicability.

The present invention was made in consideration of this situation andhas as its object the provision of a system facilitating masking workfor all types of workpieces without requiring skill on the part of theworker.

SUMMARY OF INVENTION

To achieve the above object, according to a first aspect, there isprovided a masking system comprising a first detection unit whichdetects a position of an object, an object gripping unit which grips theobject, a coating unit which coats an adhesive, a masking piece grippingunit which grips a masking piece to be attached to a masking location ofthe object, a second detection unit which detects a position of themasking piece which is gripped by the masking piece gripping unit, and arobot, wherein the robot performs first conveyance work of making theobject gripping unit grip the object and set the object at apredetermined position based on positional information of the objectwhich was detected by the first detection unit, coating work of makingthe coating unit coat an adhesive on a masking location of the objectwhich is set at the predetermined position, and second conveyance workof making the masking piece gripping unit adhere the masking piece tothe masking location of the object based on positional information ofthe masking piece which was detected by the second detection unit.

According to the second aspect, there is provided the first aspectwherein the adhesive is water soluble and has the property of increasingin viscosity by a decrease in water content and wherein the maskingpiece includes a water-absorbing material.

According to the third aspect, there is provided the first or secondaspect wherein the masking piece is cardboard.

According to the fourth aspect, there is provided any of the first tothird aspects wherein the adhesive is a material mainly comprised ofnatural rubber latex.

According to the fifth aspect, there is provided any of the first tofourth aspects wherein at least two of the first conveyance work, thesecond conveyance work, and the coating work are executed by differentrobots.

These objects, features, and advantages of the present invention andother objects, features, and advantages will become further clearer fromthe detailed description of typical embodiments shown in the attacheddrawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic view of a masking system based on the presentinvention.

FIG. 2 is a flow chart showing the operation of the masking system shownin FIG. 1.

FIG. 3A is a first view for explaining the operation of the maskingsystem.

FIG. 3B is a second view for explaining the operation of the maskingsystem.

FIG. 4A is a third view for explaining the operation of the maskingsystem.

FIG. 4B is a fourth view for explaining the operation of the maskingsystem.

FIG. 5A is a fifth view for explaining the operation of the maskingsystem.

FIG. 5B is a sixth view for explaining the operation of the maskingsystem.

FIG. 6A is a seventh view for explaining the operation of the maskingsystem.

FIG. 6B is an eighth view for explaining the operation of the maskingsystem.

FIG. 7A is a first view for explaining the operation of the maskingsystem in another embodiment.

FIG. 7B is a second view for explaining the operation of the maskingsystem in another embodiment.

FIG. 8 is a third view for explaining the operation of the maskingsystem in another embodiment.

DETAILED DESCRIPTION

Below, embodiments of the present invention will be explained whilereferring to the attached drawings. In the following drawings, similarmembers are assigned similar reference notations. To facilitateunderstanding, these figures are suitably changed in scale.

FIG. 1 is a schematic view of a masking system based on the presentinvention. In the embodiment shown in FIG. 1, the masking system 10includes multiarticulated robots with six degrees of freedom, that is, afirst robot 20 and a second robot 30. These first robot 20 and secondrobot 30 are connected to a robot controller 11. The robot controller 11is a digital computer which controls the overall operation of the firstrobot 20 and the second robot 30 and performs various processingexplained later.

As shown in FIG. 1, near the front end of the arm of the first robot 20,a first vision sensor 21 which detects the positional information of theworkpiece W is attached. Further, at the front end of the arm of thefirst robot 20, a hand 22 which grips the workpiece W is provided. Asopposed to this, near the front end of the second robot 30, a coatingunit 31 which coats an adhesive from a not shown adhesive source isattached. Furthermore, at the front end of the arm of the second robot30, a suction part 32 which picks up a masking piece M by suction isprovided. The suction pickup action by the suction part 32 is performedby a vacuum source (not shown) connected to the suction part 32.

Here, the adhesive which is coated from the coating unit 31 ispreferably one which is water soluble and has the property increasing inviscosity due to a reduction in its water content. The reason is thatwhen the later explained masking piece M includes a water-absorbingmaterial, the adhesion of the adhesive is enhanced. Alternatively, theadhesive which is coated from the coating unit 31 may be a materialmainly comprised of a natural rubber latex. In that case, it will beclear that the adhesive can be easily disposed of alone or together withthe masking piece M.

Further, as can be seen from FIG. 1, a workpiece W is carried on thetable T1. Here, the workpiece W is, for example, a frame of an armforming a not shown robot. It may also be another type of workpiece W.Further, the holding box B holds a large number of masking pieces M.These masking pieces M are sheet-shaped members of the same shape aseach other, for example, pieces of cardboard of the same shapes, and areheld stacked together inside the holding box B.

Furthermore, a staging table T2 for temporarily carrying the workpiece Wis also illustrated. Further, near the staging table T2, a second visionsensor 41 which has similar functions to the first vision sensor isinstalled fastened to the floor of the work location. These table T1,staging table T2, second vision sensor 41, and holding box B arepositioned within the operating ranges of the first robot 20 and secondrobot 30. Further, the positional relationships and dimensions of thetable T1, staging table T2, second vision sensor 41, and holding box Bare assumed to be stored in a memory part (not shown) of the robotcontrol device 11.

FIG. 2 is a flow chart showing the operation of the masking system shownin FIG. 1. Further, FIG. 3A to FIG. 6B are views for explaining theoperation of the masking system. Below, the operation of the maskingsystem 10 of the present invention will be explained while referring tothe drawings.

Note that, in the present invention, the operation of the masking system10 performed by the first robot 20 and second robot 30 includes firstconveyance work of taking out a workpiece and conveying it to apredetermined position, coating work of coating the workpiece with anadhesive, and second conveyance work of taking out a masking piece andattaching it to the workpiece. Further, when these works are finished,the workpiece with the masking piece attached to it is unloaded from themasking system and separately painted by a painting system.

At step S101 of FIG. 2, the workpiece W is detected by the first visionsensor 21. As shown in FIG. 3A, the first robot 20 is made to move tothe table T1 where the first vision sensor 21 of the first robot 20captures the image of the workpiece W. Further, the robot controller 11calculates the position and posture of the workpiece W based on theimage of the workpiece W, whereupon it is judged that detection of theworkpiece W has ended (step S102).

Then, the first robot 20 is made to move based on the position andposture of the workpiece W to a position suitable for the hand 22 of thefirst robot 20 to grip the workpiece W. Then, as shown in FIG. 3B, theworkpiece W is made to be gripped by the hand 22 of the first robot 20,then the first robot 20 conveys the workpiece W to the staging table T2.Then, as shown in FIG. 4A, the first robot 20 sets the workpiece W onthe staging table T2 (step S103). Further, after the hand 22 is opened,the first robot 20 is made to retract to its initial position. Below,the work of conveying and setting the workpiece W from the table T1 tothe staging table T2 will be called the “first conveyance work”.

The positional relationship between the table T1 and the staging tableT2 and the shape and dimensions of the workpiece W are already known, sothe position and posture of the workpiece W on the staging table T2 arecalculated based on the distance of movement of the first robot 20 fromits initial position. Then, the second robot 30 is made to move to thestaging table T2. Further, as shown in step S104 and FIG. 4B, thecoating unit 31 of the second robot 30 is started up to coat an adhesiveat a desired location of the workpiece W in exactly the desired amount(hereinafter simply referred to as the “coating work”).

When the coating work ends, the second robot 30 is made to move from thestaging table T2 to the holding box B. Inside the holding box B, aplurality of masking pieces M are arranged stacked together. In stepS105 and FIG. 5A, the suction part 32 of the second robot 30 is startedup to pick up by suction one masking piece M from the holding box B.

Then, the second robot 30 makes the masking piece M which has beenpicked up by suction move to the second vision sensor 41. Further, asshown in step S106 and FIG. 5B, the second vision sensor 41 captures animage of the masking piece M picked up by suction by the suction part 32of the second robot 30. Due to this, the robot controller 11 calculatesthe position and posture of the masking piece M based on the image ofthe masking piece M. Further, when the position and posture of themasking piece M are calculated, it is judged that the detection of themasking piece M has ended (step S107).

Then, as shown in step S108 and FIG. 6 a, the second robot 30 is made tomove to the staging table T2. Further, the second robot 30 attaches themasking piece M to the location of the workpiece W where the adhesive iscoated based on the position and posture of the workpiece W and theposition and posture of the masking piece M on the staging table T2. Inthe present invention, an adhesive is used to attach the masking piece Mto the workpiece W, so the masking piece M can be easily attached to allsorts of workpieces W without regard as to the materials or shapes ofthe workpieces W.

After this, the second robot 30 is made to retract to its initialposition and the first robot 20 is made to move to the staging table T2.Further, the hand 22 of the first robot 20 grips the workpiece W withthe masking piece M attached and unloads it from the staging table T2.The masking piece M is used so that the workpiece W is provided with anoncoated location. Therefore, in the later coating process, theworkpiece W can be coated at places other than the noncoated location.

In this way, in the present invention, the first conveyance work, thesecond conveyance work, and the coating work are performed by the firstrobot 20 and the second robot 30. Therefore, without requiring skill onthe part of the worker, the masking piece M can be attached to theworkpiece W with a high precision. Furthermore, in the presentinvention, the time required for masking work can be greatly shortenedcompared with when a worker uses masking tape, therefore the productioncapability can be raised. Further, the masking piece M is, for example,inexpensive cardboard, so it will be understood that compared with whenusing expensive masking tape etc., the masking work can be performedinexpensively.

Note that, in the embodiment explained from FIG. 2 to FIG. 6B, the firstrobot 20 and the second robot 30 are used. However, a single robot mayalso perform the first and second conveyance works and the coating work.In this case, it is possible to reduce the space required for themasking system 10. Further, the first and second conveyance works andthe coating work may be performed by three separate robots. In thiscase, it will be understood that the time required for the masking workcan be further shortened.

In this regard, FIG. 7A is a view for explaining the operation of themasking system in another embodiment. In FIG. 7A, the image of workpieceW which is gripped by the hand 22 of the first robot 20 is captured bythe second vision sensor 41. This step is preferably performed betweenstep S102 and step S103 shown in FIG. 2. Due to this, it is possible tocalculate the position and posture of the workpiece W actually grippedby the hand 22, so when placing the workpiece W on the staging table T2,the precision of positioning of the workpiece W can be further improved.

Further, FIG. 7B is a view for explaining the operation of the maskingsystem in still another embodiment. In FIG. 7B, the second robot 30 isprovided with an additional vision sensor 41 a. Between step S103 andstep S104 shown in FIG. 2, the additional vision sensor 41 a captures animage of the workpiece W carried on the staging table T2. Due to this,it becomes possible to calculate the position and posture of theworkpiece W carried on the staging table T2, so the coating work ofcoating the workpiece W with an adhesive can be performed with furtherhigher precision.

Furthermore, FIG. 8 is a view for explaining the operation of themasking system in another embodiment. In FIG. 8 as well, the secondrobot 30 is provided with an additional vision sensor 41 a. Between stepS104 and step S105 shown in FIG. 2, the additional vision sensor 41 acaptures an image of the masking pieces M inside the holding box B. Dueto this, it becomes possible to take out a masking piece M from theholding box B with a high precision. It will be understood that this isparticularly advantageous where there is a variation in position in themasking pieces M inside the holding box B.

EFFECTS OF INVENTION

In the first aspect, the first conveyance work, the second conveyancework, and the coating work are performed by robots, so it is possible toattach a masking piece to an object with a high precision withoutrequiring skill on the part of the worker. Furthermore, since anadhesive is used to attach the masking piece, the masking piece can beeasily attached to all sorts of objects without regard as to thematerials or shapes of the objects and high quality painting can berealized. Furthermore, the time requiring for the masking work can begreatly shortened compared with the case of the work being performed bya worker using masking tape, therefore the production capability isimproved.

In the second aspect, it is possible to easily improve the adhesion.

In the third aspect, it is possible to perform the masking workinexpensively compared with when using expensive masking tape etc.

In the fourth aspect, it is possible to keep down the load on theenvironment at the time of disposing of the adhesive.

In the fifth aspect, it is possible to use a plurality of robots so asto further shorten the time required for work.

While typical embodiments were used to explain the present invention, aperson skilled in the art would understand that the above-mentionedchanges and other changes, deletions, and additions can be made withoutdeparting from the scope of the present invention.

The invention claimed is:
 1. A masking system comprising: a firstdetection unit configured to detect positional information and postureinformation of an object, an object gripping unit configured to gripsaid object, a coating unit configured to coat an adhesive, a maskingpiece gripping unit configured to grip a masking piece and to attach themasking piece to a masking location of said object, a second detectionunit configured to detect positional information and posture informationof said masking piece gripped by said masking piece gripping unit, and arobot with a robot controller, wherein said robot controller isconfigured to control the robot to perform first conveyance work ofmaking said object gripping unit grip said object and set the object ata predetermined position based on the positional information of saidobject detected by said first detection unit, coating work of makingsaid coating unit coat the adhesive on the masking location of theobject which is set at said predetermined position, and secondconveyance work of making said masking piece gripping unit adhere saidmasking piece to the masking location of said object based on thepositional information of said masking piece detected by said seconddetection unit and the positional information of said object detected bysaid first detection unit.
 2. The masking system according to claim 1,wherein said adhesive is water soluble and has the property ofincreasing in viscosity by a decrease in water content and wherein saidmasking piece includes a water absorbing material.
 3. The masking systemaccording to claim 1, wherein said masking piece is cardboard.
 4. Themasking system according to claim 1, wherein said adhesive is a materialmainly comprised of natural rubber latex.
 5. The masking systemaccording to claim 1, wherein said first conveyance work is executed bya first robot and said second conveyance work and said coating work areexecuted by a second robot.
 6. The masking system according to claim 2,wherein said first conveyance work is executed by a first robot and saidsecond conveyance work and said coating work are executed by a secondrobot.
 7. The masking system according to claim 3, wherein said firstconveyance work is executed by a first robot and said second conveyancework and said coating work are executed by a second robot.
 8. Themasking system according to claim 4, wherein said first conveyance workis executed by a first robot and said second conveyance work and saidcoating work are executed by a second robot.
 9. The masking systemaccording to claim 1, wherein the robot comprises a first robotincluding the first detection unit and the object gripping unit; and asecond robot including the coating unit and the masking piece grippingunit.
 10. The masking system according to claim 1, wherein the firstdetection unit is configured to detect the positional information of theobject from above, and the second detection unit is configured to detectthe positional information of the masking piece from below.